Someone posted a request to allow an assignment to be muted without muting the Peer Review feedback. A professor here has the inverse of that request: Mute the peer review feedback without muting the assignment. His reasoning is:
"My students told me that the peer reviews they write that their peers can read sound much different than the reviews they write when the instructor is the only reader…"
I have to say that this corresponds to my own experience as a peer reviewer, and is an understandable aspect of human nature.